If he wants all his files from the laptop, and they are both windows XP then you can use the Windows Files and Setings Transfer Wizard, and the easiest way to do it is to have a network cable connecting the laptop and the desktop to create a small Local Area Network between them.

You first have to run the wizard on the old computer, and save the old files in the shared documents folder on the other computer through the network. Its a mater of just following the instructions on screen and youll do fine.

If its only music that he wants transfered, then the easiest way is to use a flash drive like rifle suggested, or you can always burn a CD/DVD